Disk drives are information storage devices that use magnetic media to store data and a movable read/write head positioned over the magnetic media to selectively read data from and write data to the magnetic media.
Typically, referring to FIG. 1, a disk drive contains a number of magnetic disks 6 attached to a common spindle motor for rotation. The surface of the magnetic disk 6 suspends an associated head arm assembly that includes a head gimbal assembly (HGA) 1. The head gimbal assembly 1 is generally attached to and mounted on a drive arm 4. A voice-coil motor (VCM) 5 is connected to the drive arm 4 for controlling the motion of the drive arm 4 and, in turn, controlling a magnetic transducer incorporated by a head slider 2 of the HGA 1 to position with reference to data tracks across the surface of the magnetic disk 6, thereby enabling the magnetic transducer to read data from or write data to the disk 6.
The HGA 1 serves to dynamically adjust the orientation of the head slider 2 to conform to the disk surface while the disk 6 is being spun by the spindle motor. More specifically, the HGA 1 generally comprises a suspension to load or suspend the slider thereon. The suspension includes a load beam, a base plate, a hinge and a flexure, all of which are assembled together. The load beam is connected to the base plate by the hinge, and the base plate is used to enhance structure stiffness of the whole HGA. The flexure is made of flexible material and runs from the hinge to the load beam. One end of the load beam is mounted to the drive arm by means of the base plate, and the other end of the load beam is attached to the flexure. The load beam biases the head slider toward the surface of the magnetic disk, while the flexure provides flexibility for the head slider. A suspension tongue is provided at an end of the flexure to carry the head slider thereon.
Referring now to FIGS. 2a-2b, conventionally, the head slider 2 typically has a transducer provided on a trailing surface 23 thereof for reading and writing data on the concentric data tracks of the disks 6, as is well known in the art. For electrical connection, the transducer provides several bonding pads 24 formed on the trailing surface 23 of the head slider 2, and the flexure 3 provides corresponding bonding pads 10 which are already common with transducer traces extending from a read/write electronic circuit (not shown) of the disk drive. The transducer traces serve to conduct signals between the transducer and the read/write electronic circuit for control. The bonding pads 24 of the transducer are respectively soldered or ultrasonically bonded with bonding pads 10 of the flexure 3 via solder or metal balls 8 thus implementing electrical connection therebetween. In addition, for achieving a strong physical bonding performance, epoxy adhesive 7 is applied to a top surface 22 of the head slider 2 facing the flexure 3 and opposite the air bearing surface 21 of the head slider 2, and the epoxy adhesive 7 bonds the top surface 22 of the head slider 2 to the flexure 3.
However, the method for interconnection the head slider 2 and the flexure 3 of the suspension described above is complicated. As is illustrated above, the head slider 2 is designed to be attached with the flexure 3 firstly by bonding solder or metal balls 8 between corresponding pads and secondly by applying epoxy adhesive 7 to fix the head slider 2 and the flexure 3 firmly. The electrical and mechanical connection between the head slider 2 and the flexure 3 are two separate assembly processes, which are time-consuming and laborious.
More recently, consumers are constantly desiring to decrease the cost of head sliders. To decrease the cost of head slider, slider size is subjected to be designed smaller and smaller so that one wafer can be separated to more head sliders. Because of the head slider's size decreasing, the area of the trailing surface 23 has become smaller too. Simultaneously, with the improvement of slider technology, more and more functional bonding pads 24 are required to be added on the trailing surface 23. Thus, a smaller size head slider can no longer provide enough space for bonding connection at the slider's trailing surface 23. On the other hand, the traditional interconnection between the head slider 2 and the flexure 3 at the trailing surface 23 by solder or metal balls 8 can be damaged by shock stress or even cracked because the head slider 2 and the flexure 3 may rotate relative to each other about the interconnection point.
At present, a more advanced typical interconnection between the head slider and the suspension has been introduced to solve the above problems. The head slider provides a plurality of slider electrical bonding pads on the top surface opposite to the air bonding surface thereof, and the suspension provides a plurality of corresponding flexure electrical bonding pads. The slider electrical bonding pads are bonded to the flexure electrical bonding pads via bonding solder or metal balls to establish mechanical and electrical interconnection between the head slider and the suspension. In this case, the top surface of the head slider can provide enough space for arranging slider electrical bonding pads, and the interconnection between the head slider and the suspension prevents rotation therebetween. However, this method may introduce another problem. As the head slider is supported by solder bonding without any datum, the head slider's static pitch attitude and static roll attitude may vary, and accordingly, the variation of pitch and roll attitude will cause variation of slider flying height, which degrades flying performance of the head slider, as well as data reading/writing performance.
Hence, a strong need has arisen for providing a head gimbal assembly with an improved interconnection between the head slider and the suspension, a magnetic disk drive with the improved head gimbal assembly, and an improved method for fabricating the head gimbal assembly to overcome the above disadvantages.